1. Field Of The Invention
The present invention relates to hearing aids, and more particularly pertains to an improved cover for BTE hearing aids (behind-the-ear) of the type possessing an arcuately curved microphone, amplifier and control portion adapted to be worn externally over the upper rear portion of a user's ear. This conventional type of hearing aid includes an in-ear mold connected to the amplifier and control portion by a sound tube for transmitting amplified sounds to the user's ear. BTE hearing aids are typically used by individuals having a relatively severe hearing loss which can not be corrected by the smaller in-ear and ear canal insertable type hearing aids. Accordingly, such externally worn BTE hearing aids are susceptible to exposure to moisture and other contaminants. The case of a BTE hearing aid houses sensitive microphone, amplifier, controls and battery components of the hearing aid. The hearing aid case is not hermetically sealed, but rather includes openings and cracks adjacent the volume control wheel, on/off switch and battery compartment door. BTE hearing aids are frequently exposed to moisture from ambient humidity, precipitation, perspiration, shower or bath water, and other contaminants such as dust and hair care products. Such moisture and other contaminants can and frequently do enter the case through the various cracks, damaging the internal circuitry and switches of the hearing aid, principally by promoting corrosion, necessitating expensive repair or replacement. A typical BTE hearing aid costs about $700.00, with an average repair costing more than $100.00 and taking at least one week, during which time the user is deprived of the hearing aid. As there are currently six to eight million BTE hearing aids in use in the United States, and one and a half million new BTE hearing aids sold annually in the United States, the prevention of damage to BTE hearing aids from moisture and other contaminants is of substantial interest.
2. Description of The Prior Art
The problem of damage to BTE hearing aids caused by moisture and other contaminants has been well known for several decades. Yet, no practical workable solution to the problem has been available in the market, until the introduction of the hearing aid cover of the present invention. Prior art solutions to the problem have been found unsatisfactory for a variety of reasons. One proposed solution, currently available on the market, involves wrapping the hearing aid case with a narrow elongated plastic wrap strip. This proposed solution has not been found satisfactory, because the openings in the resulting wrapping formed at the overlapping edges of the helical windings tend to induce moisture into the interior of the wrapping and into the hearing aid case by the mechanism of capillary action. Additionally, the volume control wheel and on/off switch of the hearing aid can not be operated without removing the plastic wrapping. Another prior art proposal addressed to the problem involved dipping the hearing aid case into a liquid plastic in an effort to form a seal. This method was found unsatisfactory because the liquid plastic was induced by capillary action into the cracks of the hearing aid case, obstructing operation of the volume control wheel and on/off switch. Additionally, because many BTE hearing aids use air activated zinc batteries which must have exposure to air to work, this method proved unsatisfactory because the liquid plastic sealed the battery compartment, resulting in battery failure. Accordingly, the most common method employed by BTE hearing aid users to attempt to minimize moisture damage to their hearing aids involves placing the hearing aid into a closed container with silica gel, a granular material which absorbs moisture. Of course, this method does not prevent the induction of moisture into the hearing aid case while in use, but merely attempts to remove the moisture as rapidly as possibly during periods of non-use thus minimizing the amount of corrosion and other damage sustained by the hearing aid.